Cherniukh Ihor, Sekh Taras V, Rainò Gabriele, Ashton Olivia J, Burian Max, Travesset Alex, Athanasiou Modestos, Manoli Andreas, John Rohit Abraham, Svyrydenko Mariia, Morad Viktoriia, Shynkarenko Yevhen, Montanarella Federico, Naumenko Denys, Amenitsch Heinz, Itskos Grigorios, Mahrt Rainer F, Stöferle Thilo, Erni Rolf, Kovalenko Maksym V, Bodnarchuk Maryna I
Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland.
Swiss Light Source, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
ACS Nano. 2022 May 24;16(5):7210-7232. doi: 10.1021/acsnano.1c10702. Epub 2022 Apr 6.
Nanocrystal (NC) self-assembly is a versatile platform for materials engineering at the mesoscale. The NC shape anisotropy leads to structures not observed with spherical NCs. This work presents a broad structural diversity in multicomponent, long-range ordered superlattices (SLs) comprising highly luminescent cubic CsPbBr NCs (and FAPbBr NCs) coassembled with the spherical, truncated cuboid, and disk-shaped NC building blocks. CsPbBr nanocubes combined with FeO or NaGdF spheres and truncated cuboid PbS NCs form binary SLs of six structure types with high packing density; namely, AB, quasi-ternary ABO, and ABO types as well as previously known NaCl, AlB, and CuAu types. In these structures, nanocubes preserve orientational coherence. Combining nanocubes with large and thick NaGdF nanodisks results in the orthorhombic SL resembling CaC structure with pairs of CsPbBr NCs on one lattice site. Also, we implement two substrate-free methods of SL formation. Oil-in-oil templated assembly results in the formation of binary supraparticles. Self-assembly at the liquid-air interface from the drying solution cast over the glyceryl triacetate as subphase yields extended thin films of SLs. Collective electronic states arise at low temperatures from the dense, periodic packing of NCs, observed as sharp red-shifted bands at 6 K in the photoluminescence and absorption spectra and persisting up to 200 K.
纳米晶体（NC）自组装是一种用于中尺度材料工程的通用平台。NC的形状各向异性导致了球形NC无法观察到的结构。这项工作展示了多组分、长程有序超晶格（SLs）中广泛的结构多样性，这些超晶格由高发光性的立方CsPbBr NCs（以及FAPbBr NCs）与球形、截顶长方体形和盘形的NC构建块共同组装而成。CsPbBr纳米立方体与FeO或NaGdF球体以及截顶长方体形的PbS NCs结合，形成了六种具有高堆积密度的二元SLs结构类型；即AB型、准三元ABO型和ABO型以及先前已知的NaCl型、AlB型和CuAu型。在这些结构中，纳米立方体保持取向相干性。将纳米立方体与大而厚的NaGdF纳米盘结合，会形成类似于CaC结构的正交SL，在一个晶格位置上有成对的CsPbBr NCs。此外，我们还实现了两种无基底的SL形成方法。油包油模板组装导致形成二元超粒子。以三醋酸甘油酯为亚相，在干燥溶液的液 - 气界面上进行自组装，得到了SL的扩展薄膜。在低温下，由于NC的密集、周期性堆积产生了集体电子态，在光致发光和吸收光谱中，于6 K时观察到尖锐的红移带，并且一直持续到200 K。
